Indian J.Hiff Farmg. 11(1&2) : 39 ~ 43 1998
INHERITANCE OF PHOTOPERIOD INSENSITIVITY AND GENETIC RELATIONSHIP OF GRAIN YIELD WITH SOME
OTHER ATTRIBUTES IN SCENTED RICE
!"
A.
Talukdar* and P. Talukdar
Department
of PlantBreeding and Gentles
AssamAgricultural
UniversityJorhat - 785013. Assam
"'RARS, Gosatgaon - 783 360, Kokrajhar, Assam
.'
ABSTRACT
Scented rice varieties are highly priced for its unique aroma, grain quality and palatability, but poor yielder and mostly photoperiod sensitive. Five F2generation crosses of photoperiod insensitive and photoperiod sensitive varieties of scented rice were tested for inheritance of photoperiod insensitivity during ahu season (March sowing). The crosses, Rangajaha x Rasi, Borjaha x Ratna, Rangajaha x Ratna, Chufanjaha )( Ratna and Arabjaha )( Jaya seg regated at a ration of 15 photoperiod sensitive: 1 photoperiod insensitive indicating the involvement of two dominant duplicate genes for control of photoperiod insensitivity. Sterility percentage, number of effective tillers/plant, days to flowering and maturity.
1OO~grainweight and paincle length may be effective criteria for selection of plant for yielld imporvement. Grain yield was positively.
associated with number of effective tillers per plant and number of grains per panicle and negatively with sterility percentage at both genotypic and phenotypic levels.
INTRODUCTION
Scented rice varieties are highly priced for its unique aroma, grain quality an palatability.
But, they are poor yielder and mostly photoperiod sensitive. Hence, to increase the production and productivity of this class of rice, it is Important to study the genetics of photoperiod insensitivity and aroma nad interrelationshipofyieJd with other characters in orderto formulate breeding strategy to transfer this particular trait to varieties with scent and other desirable traits. Several workers studied this character in non-scented rice and arrived at diverse interpretations. The present investigation was therefore, undertaken in indigenous scented rice to unearth the genetics of this particular trait in order to facilitate development of photoperiod insensitive high yielding aromatic rice varieties.
39
--.-..-...--~..,"--_"-,_, -_-------.-~-..-.---._.,~---'~''''
._.
,_..-.-'-..~-~ ~..-.---- ----~~.'-'~MATERIALS AND METHODS
The materials consists of five F2 populations of four indigenous scented photoperiod sensitive and three high yielding, photoperiod insensitive varieties of rice. The materials were developed during saliseason (July sowing) of 1990. The F2 plants alongwith the parents were laid in RBD with three replications each during long day length ahu season (March sowing) in 1991. The individual plants within each cross which came to flower were identified as photoperiod insensitive and the rest non flowering plants as photoperiod sensitive. The ration between photoperiod insensitive and sensitive plants was worked out and tested for goodness of fit by computing
X2
(chi-square) values. The observations on qraln yield per plant, days to first flowering, plant height, number of effective tillers per plant, panicle length, number of grains per plant, sterility percentage and 1DO-grain weig ht were recorded from sampled flowered plants of the crosses and sample plants of the parents. The mean data were subjected to anallysis of variance and covariance to estimate biometrical parameters following standard procedures.RESULTS AND DISCUSSION
The subject of flowering response of rice plant to change in day length is complex and results can only be achieved by devising suitable techniques. But in present study, the technique was restricted the use of natural variation in day length atJorhat from February to Octorber. The day-length (excluding twilight) begins to increase above
12
hours after summer equinox on 21st March and falls below 12 hours after winter equinox on 21st September.Based upon this fact the inheritance pattern of photoperiod insensitiveness was studied and is presented in Table 1. The F2 segregation can satisfactorily be explained by the action of two pairs of genes. In Rangajaha x Rasi, a pattern of 99 sensitive to
6
insensitive plants were obtained in the F2populations indicating a segregation ratio of 15:1 which would involve two dominant genes controlling photoperiod sensitivity. This postulates can also be applied to Rangajaha x Ratna cross in which 110 sensitive and 10 insensitive F2 plants were classified.Another F2 populations Arabjaha x Jaya, gave 97 sensitive to 8 insensitive F2 plant which indicated a good agreement with 15:1 ratio. Since the F2sensitive: 1 insensitive, it is reasonable to bellieve that two duplicate dominant genes control photoperiod sensitivity.
It was, however, observed that not all the insensitive plants in each of F2 population followed at one date, rather in stretched over a period of time. The mean data for days to flowering were 118,114,115,109 and 119 for Rangajaha x Rasi, Borjaha x Ratna, Chufanjaha
x Ratna, Rangajaha x Ratna and Arabjaha x Jaya, respectively. Few plants in the cross Borjaha x Ratna, Rangajaha x Ratna and Arabjaha x Jaya flowered earlier to its parents under consideration and thus exhibited transgressive segrgationtowards earliness which could be exploited in breeding for early matu ring va rieties.. . '.
The fact that not all the insensitive plants flowered together, indicated the possible interaction of photoperiod insensitive genes with environmental conditions for its expression.
It was observed in the cross combinations that most of the plants flowered during the month of June which possessed a favourablle enviornrnental conditionstor the crop (Table 3). During
• . ._ .. , "__ . .__"'~_'_~_~ ~_~ __ ,_.t..-.,.__,._. , _
photoperiod sensitivity with temperature and the resultant effect on flowering duration reported long back by Japanese workers (summarized by Moringa, 1954). Moreover, the role of modifiers in the expression of the insensitive genes can not altogether be ruled out. The existence of i-Efgene which inhibits the genes for early flowering (Ef), was also reported by earlier by Chang et al. (1969). All these information necessitate the importance of critical study on the insensitive plants obtained in the present investigation, to establish proper genetic system working on it.
The estimates of genetic parameters are presented in Table 2. The highest geoot~pic coefficient of variation was recorded for sterility percentage
(3-2.3.2%)
follo.wed by number of effective tillers per plant (10.91 %) and grain yield per plant (1'0.07%). High heritabillity estimates were recorded for days to maturity, days to flowerilng, 1'OO~grainweight, panicle length, sterility percentage and grain yield per plant The gen.etic advance for the above characters were moderate to hig h indicating the eperation of additive gene action. Therefore, it can be inferred that selection for the above traits are likely to accumulate more additive genes leasing to further improvement in their performance. The estimates of genotypic and phenotypic correlation coefficients between grain yield per plant and other attibutes revealed a strong positive association of grain yield per plant with number of effective tilliers per plants and number of grains per panicle while negative association was evident with sterility percentage at both the genotypic and phenotypic levels. Similar results were earlier reported by Talukdar et al. (1997); Ghosh et al. (1981) and Prasad et at. (1988). The result thus suggested a scope for development of high yielding photoperiod in sensitive scented rice varieties through direct but critical selection for these characters.REFERENCES
Chang, T, Li, C. and Vergaram, B. S. (1969). Component analysis of duration from seeding to heading in rice by the basic vegetative phase and photoperiod sensitive phase.
Euphytica, 18:79-91.
Ghosh, S .• Sinha, M. M_ and Saran, S. (1988). Effect of late sowing on spikelet sterility in rice. Oryza,25:417-417.
4 Moringa, T (1954). Studies on the photoperiodism in rice (Abstract of Japanese Literature).
Reports for the fifth meeting of the t. R. C. working party on Rice Breeding, Tokyo:
21-34.
Prasad, G. S.
v.,
Prasad,A.
S.R.
Sastry, N.V.
S. ad Srinivasan, TE.
(1988). Genetic relationship among yield components in rice. IndianJ.
Agric. Sci. 58:470-472.Talukdar,
A.
and Talukdar, P. (1997). Inheritance of scent and genetic relationship of grain yield with some other attributes in scented rice. Oryza, 34: 171-173.41
Table 1. Inheritance of photoperiod insensitivity
Cross Number of F2 elants Ration
X2
value PvalueNot-flowered (NF) Flowered (F) Observed Expected Observed Expected
Rangajaha xRasi 99 98.44 6 6.56 15.1 0.053 0.90
0.80
Borjaha xRatna 123 126.56 12 8.44 15:1 1.66 0.20
0.10
Chufanjaha xRatna 11 112.50 6 7.50 15:1 0.32 0.70
0.50
Rangajaha xRatna 110 112.50 10 7.50 15:1 0.88 0.50
0.30
Arabjaha xJaya 97 98.44 8 6.56 15.1 0.33 0.70
0.50
Table 2. Genetic parameters for different characters recorded on segregating population of five photoperiod sensitive xinsensitive crosses and their parents Character Genotypic Heritability Genetic Correlation coefficients coefficient of in broad advance as rg
rp
variation (%) sense(%) %of meanDays to first fl oweri ng 7.66 83.66 14.44 -0.016 0.145
Days to maturity 5.78 86.83 11.09 0.003 0.091
Plant height 7.37 54.66 11.23 0.205 0.293
Number ofeffective tillers per plant 10.91 59.25 17.29 0.880** 0.870··
Panicle length 8.74 73.09 15.42 0.354 0.200
Number of grai ns per penicl e 8.44 55.61 12.96 0.735** 0.830"
Sterility percentage 32.32 72.07 56.52 -0.980·* -0.615-
100-grain weight 9.76 74.68 17.37 -0.379 -0.241
Grain yield per plant 10.07 62.03 16.30
Table 3. Meteorological data (1991)
Month Mean temperature (0G) Mean relative humidity
(%)
Mean total rainfalMax. Min. Average Moming Evening Average (mm)
February 25.1 12.2 18.65 92 65 78.5 41.1
March 18.1 16.5 17.30 82 60 71.0 31.7
April 27.7 18.9 23.30 87 67
no
151.1May 27.9 21.9 24.90 91 77 84.0 306.2
June 31.2 25.0 28.10 91 78 84.5 342.3
July 32.7 26.0 29.35 88 25 81.5 322.7
August 32.5 26.1 29.30 90 76 83.0 373.9
September 31.0 24.7 27.85 91 78 84.5 360.9
43
